Nans mourns death of 11 unimaid students

I think there may be a small mistake in your sentence. It seems like you meant to say "NANS mourns death of 11 UNIMAID students".

NANS stands for National Association of Nigerian Students, and UNIMAID stands for University of Maiduguri. If that's correct, here's a possible rewritten sentence:

The National Association of Nigerian Students (NANS) has mourned the death of 11 students of the University of Maiduguri (UNIMAID).

Please let me know if I'm correct or if there's anything else I can help you with!